Clean constructionNew cement absorbs CO2

Concrete — the essential material used by the world’s $3.8 trillion construction industry — accounts for 5 percent of the world’s man-made carbon dioxide emissions; each ton of cement emits about 800 kg (1,763 lb.) of CO2 during manufacture — and every year, some 3 billion tons of cement turn into nearly 30 billion tons of concrete, a British start-up has devised a new cement — based on magnesium silicates rather than limestone — that absorbs and stores CO2 when it is produced

In 1824 English stone mason Joseph Aspdin invented Portland cement in his kitchen and patented what has remained the primary material used in concrete ever since. Trouble is, global demand for cement — a $130 billion annual business — is increasing quickly but the process used to make it already produces an estimated 5 percent of the world’s man-made carbon dioxide emissions. It took 184 years, but now another English company, Novacem, has come up with a different formula — one which absorbs more carbon than it releases.

Jennifer L. Schenker writes that the 2-old company, which was spun out of London’s Imperial College, has built the first cement works in central London since the Romans, with an eye toward becoming the first great cement company of the twenty-first century. “Cement is a vital strategic material and the glue that holds the world together,” says Stuart Evans, Novacem’s chief executive officer. “There is a lot more science and technology in cement and concrete than you would imagine.”

Novacem is among thirty-one enterprises named on 1 September by the Geneva-based World Economic Forum as Tech Pioneers offering new technologies or business models that could have a positive impact on people’s lives. It is one of six in this year’s class that are either reengineering basic building blocks used in the $3.8 trillion construction industry or developing other ways to make buildings “greener” and more energy-efficient.

Buildings’ big footprint

The rising interest in green buildings is being spurred by economics, scarcity, and the environment, according to a report by New York-based strategic advisory firm Lux Research. Construction, operation, and maintenance of the buildings where we eat, sleep, work, and visit represent the single largest source of energy and material consumption of any human activity, the report says.

Buildings consume 40 percent of the U.S. annual energy (and a comparable amount throughout the rich world), including 72 percent of electricity and 34 percent of natural gas just for heating and cooling. Some 40 percent of all raw materials produced each year — including concrete, steel, glass, wood, and ceramics — are used in buildings.

Schenker writes that the carbon dioxide (CO2) released in producing building materials is also substantial and has been targeted as a leading contributor to global climate change. Each ton of cement emits about 800 kg (1,763 lb.) of CO2 during manufacture. This is because cement is made from limestone, which releases a